Memory mechanism for pushbutton tuners

ABSTRACT

For a pushbutton radio tuner, a mechanical memory mechanism having a plurality of memory cams positioned at axially spaced apart locations on a common shaft. The shaft is rotated by actuation of a pushbutton which has a portion thereof engaging one of the memory elements to tune the radio to a desired preselected radio station. A common lock mechanism is used to unlock all of the cams on the shaft, and friction holding means is provided for each cam to hold the cams that are not being set in a fixed position on the shaft, while other cams are being set on the shaft. The cam being set is moved only under the influence of a setting action by its associated pushbutton.

I O United States Patent [151 3,667,302 Olah [451 June 6 1972 54] MEMORY MECHANISM FOR 2,278,648 4 1942 DeRoo ..74/l0.37

PUSHBUTTON TUNERS v Primary ExaminerMilton Kaufman [72] Inventor: Emery E. Olah, Des Plaines, lll Atwmey Mue]]er and Aichele [73] Assignee: Motorola, Inc., Franklin Park, Ill.

[57] ABSTRACT [22] Filed: Oct. 13, 1970 For a pushbutton radio tuner, a mechanical memory [2 pp N01 80,295 mechanism having a plurality of memory cams positioned at axially spaced apart locations on a common shaft. The shaft is [52] U S Cl 74/10 37 334/7 rotated by actuation of a pushbutton which has a portion [51] i 1 35/18 thereof engaging one of the memory elements to tune the l 58] Fieid 27 1O 33 radio to a desired preselected radio station. A common lock 2 6 l 34/7 mechanism is used to unlock all of the'cams on the shaft, and friction holding means is provided for each cam to hold the cams that are not being set in a fixed position on the shaft, 56] References Cited while other cams are being set on the shaft. The cam being set UNITED STATES PATENTS is moved only under the influence of a setting action by its associated pushbutton. 2,288,098 6/1942 Marholz et al ..74/lO.37 Y 1 2,260,429 10/1941 Barrett ..74/10.37 4 Claims, 5 Drawing Figures 43 y F" ll M w s \xszls, A\ t\\\\\\ t@ ///w m if, r A /:\s Q u- J N "i- 55 f;

Q r1 1 k 5. I w IIIA a MW t 4: A; l *"Vl 4o IIIIIIIII /A g 1? PATENTEUJUH 6|972 3,667,302

sum 10F 2 INVENTOR.

EMERY E. OLAH ATTORNEYS.

MEMORY MECHANISM FOR PUSI-IBU'I'ION TUNERS BACKGROUND OF THE INVENTION This invention relates generally to pushbutton tuning mechanisms for radio receivers, and more particularly to an improved locking device for use in setting and resetting an adjustable pushbutton structure to permit selection of a predetermined group of given stations.

In radio tuners heretofore provided, it is common to have an adjustable cam member supported on each one of a plurality of slideably mounted plunger rods. The cam member engages a treadle bar structure which includes a pair of parallel members mounted on a movable carriage and coupled to the tuning elements of the radio receiver to manipulate the same. In such mechanisms, the cam member is locked at a certain angle on a pushbutton plunger rod so that as the rod is moved, with respect to the parallel bars of the treadle structure, it brings it into alignment with the extended surfaces of the cam on the plunger rod. This sets the carriage and the resonant circuits of the radio tuner to a proper preselected position thus corresponding to a preselected radio station.

SUMMARY OF THE INVENTION Therefore, it is an object of this invention to provide an improved cam locking mechanism for setting and resetting selected ones of a group of radio stations on a pushbutton tuner.

Another object of this invention is to provide an improved pushbutton tuner assembly which is simple in construction, inexpensive to manufacture and requires less assembly time so as to reduce labor costs.

Briefly, the tuning mechanism of this invention includes a common rotating shaft, which replaces the treadle bar assembly of the prior art, and which has a number of memory plates or cams attached thereto at longitudinally spaced apart locations. The cams are attached to the shaft in such manner that with the locking device unlocked any one cam can be rotated against a predetermined friction without affecting the position of other cams on the shaft, thus setting or resetting a given cam to a desired radio station will not affect the other cams. A locking device is provided at one end of the shaft to operate in such a manner than when the locking device is in its ON" condition, it locks all the cams in a fixed position on the shaft, and in its OFF condition, it unlocks all the cams so that selected ones can be rotated against a given amount of friction while being moved to a set position. A forked shaped pushbutton slide member is actuated by pressing it inward so that the forked portions thereof engage radially extending cam surfaces. The rotating shaft can have an infinite number of relative angular positions with respect to any memory cam fastened thereto. The same pushbutton fork member is used to set the cam, when unlocked, as it is used to reset the cam to a preselected radio station. That is, setting of the cam takes place with the clamping or locking device in an OFF condition and sufiicient frictional force is provided so that only the cam which is being set is rotated to a new position, and resetting of the cam takes place with the clamping or locking device in an ON condition to lock the cam on the shaft so that both rotate to a preselected position.

When the cams are in the unlocked condition, frictional force for each cam on the shaft is obtained by spring separator means which exert a slight axial pressure on the cam or to an adjacent spacer to prevent inadvertent movement of the cams not selected to be moved. The locking mechanism, however, exerts a considerable amount of force, in the order of 120 pounds or so, axially against each of the cams and spacers to lock them in a fixed position on the shaft and each cam position will correspond to a memorized radio station.

BRIEF DESCRIPTION OF THE DRAWINGS mechanism for holding and releasing the memory cams;

FIG. 2 is an exploded fragmentary, perspective view of the memory cams on the shaft with a common lock mechanism associated therewith and showing pushbuttons for operating the same;

FIG. 3 is an enlarged fragmentary, sectional view of the memory cams and shaft and common lock mechanism of this invention;

FIG. 4 is an enlarged side view showing the pushbutton memory cam mechanism of this invention; and

FIG. 5 illustrates a series of steps diagrammatically showing the operation of the memory cam and common lock mechanism of this invention. 1

DESCRIPTION OF PREFERRED EMBODIMENT Throughout the following detailed description it will be un derstood that the like reference numerals on the various figures in the drawings are intended to designate similar elements or components. FIG. 1 shows a pushbutton radio designated generally by reference numeral 10 and having a housing 12 from which extend a plurality of pushbuttons 14 to be manipulated by pressing a selected one of the pushbuttons to recall a tuning mechanism within the housing 12 to a preselected radio station. Full manual tuning may be accomplished by a knob 16 in the conventional manner and which is clutched in and out of engagement with the pushbutton mechanism in any manner well-known in the art. The proper radio station will be indicated on an indicator dial assembly 18 in the usual manner, and an ON-OFF and volume control knob 20, which may include tone control means, is provided.

In FIG. 2 there is seen the illustrated embodiment of the new and novel common lock and memory cam device of this invention which can be used for pushbutton radios and which is designated generally by reference numeral 22. The memory device 22 includes a plurality of memory cams 24 preferably at equally spaced apart locations on a shaft 25 and separated thereon by spacers 26. At one end of the shaft 25 is located a common locking mechanism designated generally by reference numeral 28 and which includes a lever 29 movable between OFF and ON positions as indicated by the double arrowed lines labeled OFF and ON, respectively.

With the common lock mechanism 28 in the ON or locking position, all of the memory cams 24 are locked in position on the shaft 25 and are non-movable relative thereto. Upon actuation of any of the pushbuttons 14, a rearwardly extended member 30 will engage the associated memory cam 24 on the shaft 25 and rotate the shaft about its axis which, in turn, will move a lever 32 and an associated bar 34which is connected in the usual manner to the tuning coils of the radio. Rotation of the shaft will continue until the radially outwardly cam surfaces 24a and 24b both engage the spaced apart portions 30a and 30b, respectively, of the forked members 30 at which point rotation of the shaft will stop regardless of any further pressure applied thereto.

FIG. 5 illustrates a series of diagrammatic steps to show the theory of operation of the forked members 30 with their associated memory cams 24. In the first position, to the left of the drawing, the cam 24 is in the unlocked condition on the shaft 25 and held in place only by a slight frictional force, and as the forked member 30 is pushed rearward by the pushbutton 14, the portion 30a will first engage the portion 244 to rotate the cam 24 on the shaft. The shaft is maintained in a fixed position by suitable holding means providing a relatively high friction to hold the same. As the forked member 30 is movedrearwardly, the cam 24 continues to rotate about the shaft 25 until the portion 24b thereof engages the other forked member 30b so that no further rotation of the cam can take place. The arrowed line passing through the shaft 25 indicates the position of the cam 24 with respect to the shaft. No matter how the shaft is rotated after the cam 24 is locked thereon, after being set, actuation of the associated forked member 30 to engage the particular cam 24 will cause the shaft 25 always to return to the same position and tune in the previously set radio station.

The common locking mechanism 28 may be automatically actuated to lock the cam 24 on the shaft 25 upon release of the forked member 30 immediately after setting one of the cams 24 to its desired position.

Referring to FIG. 3, there is seen an enlarged sectional detailed view of the illustrated cam memory device 22 and of the common cam locking mechanism 28. Here, fragmentary portions of a support structure 40 are shown at each end of the figure pivotally to support the entire assembly about the axis of the shaft 25. A fixed end spacer 42 may be provided at one end of the shaft 25 to locate thefirst one of-the cam members 24 at the desired distance away from the end of the shaft.

Here, the shaft 25 is pivoted by a ball 43 but it will be un-' derstood that any suitable pivot means can be used. The space between the respective cams 24 is determined by the axial extent of the associated spacers 26 which are positioned between the cams. This space also includes the slight dimensional space which is provided by a holding spring 42a positioned on each side of each of the cam members 24. With the locking mechanism 28 in the unlocked or OFF condition, the cams 24 are held in place by a slight frictional force exerted thereon by the holding spring 42a which apply sufficient axial holding force on each of the cams so that unselected cams will not rotate while a selected cam is being set to a new position. In the unlocked condition of the locking mechanism 28, it will be noted that all of the cams simultaneously are unlocked and only the selected one is set to a new position; the remaining cams must be unaflected by the setting operation. Therefore, byproviding the holding spring 42a on each side of the cam, or at least on one side thereof, a sufficient holding force is obtained so that the earns 24 will not inadvertently move on the shaft 25.

' The common locking mechanism 28 is designed so as to be in a locked condition during its normal function, and actuation of the lever 29 will unlock the mechanism and the cams so that a selected cam or cams 24' can be set to a new position.

The common locking mechanism 28 has a housing portion 44 which is secured to a spacer end housing portion 46 located at the other end of the shaft 25. Within the housing portion 46 is a cavity 47 in which is located a high pressure, axial force producing spring 48 which applies pressure against the spacer end housing portion 46 and to a flange member 49 so that all the cams along the shaft 25 are firmly locked in position by this single force. This end of the shaft rotates about its axis as a result of ball bearing members 50 positioned between the flange member 49 and a wall portion 52 of the housing 44. Extendingthrough the wall portion 52 is a reduced diameter portion 540' of a plug 54 which engages a reduced end 56 of shaft 25 within the flange 49. During the locked condition of the locking mechanism, the reduced diameter portion 540 of the plug 54 is spaced from the reduced end 56, this being only in the order of a 0.001 inch or so. However, upon actuation of the lever 29, i.e., movement downward as seen on the drawing, a pair of toggle members 58 and 59 are moved into substantial alignment, thus effectively increasing their length in the order of about 0.003 inches or so to exert a force on the plug 54 which, in turn, exerts a force on the end 56 to compress the spring member 48 and release the locking forces exerted thereby. When the lever 29 is again moved to the ON or locked position, the plug 54 is urged away from the end 56 by a spring washer 60. A cap screw 61 is threaded into the other end of the housing 44 to engage the toggle member 59 and is adjustable to provide the necessary length of travel of the locking mechanism to compress the spring 48 and release its locking pressure.

FIG. 4 illustrates a partial sectional side view of a pushbutton mechanism constructed in accordance with this invention and which illustrates a few alternate configurations of the assembly. Here, the shaft 25 is designated 25a and is provided with grooves 90 apart so as to receive corresponding protuberances on the spacer washers 420 which act to lock the washers 42 rotatably on the shaft, but which provide a somewhat free axial movement thereof.

The dial indicator assembly 18 is located immediately above the extended portions of the pushbutton actuators. In this embodiment, the actuators are designated by reference numeral and include cam engaging portions 70a and 70b which are straight surfaces angled at about 45 degrees off the vertical to engage the corresponding cam surfaces 24a and 24b, respectively. The portions 70a and 70b are held firmly together so as not to spread apart by a continuous portion 70c which is on the back side of the shaft 25 and the associated cams 24 are located within an opening formed therein. That is, the pushbutton actuator 70 is provided with an opening or struck-out 7 portion 72 which forms a space into which the shaft 25 is positioned. Since the tapered edges 70a and 70b do not engage the cam portions 240 or 24b except when the cam is completely rotated to its full stop position, there is no need to heat treat the metal parts making up the pushbutton actuator 70 as there will be a minimum amount of wear of these parts. I

Although the details of construction of one form of the invention is illustrated herein, it will be understood that any structural arrangement whereby all of the memory cams of a tuner mechanism are located on a common shaft and locked and unlocked by a common locking mechanism will fall within the broad aspects of this invention.

I claim:

1, In a wave signal receiver having frequency tuning means and pushbuttons to be actuated to set and thereafter recall preselected frequencies of the tuner means to receive given radio stations, the combination including:

a housing in which the tuning means is mounted;

a shaft mounted in said housing;

link means connected between said shaft and said tuning means to cause tuning thereof in response to rotation of said shaft about its axis through a limited arcuate move? ment;

a plurality of memory cams; I

a common locking device for simultaneously locking and unlocking said cams in position on said shaft, said common locking device including an operating lever movable between first and second positions and spring biased means coupled to said memory cams and being controlled by said operating lever;

each of the pushbuttons having a portion thereof extending into said housing and engaging a respective oneof said memory cams to rotate said shaft in response to the position of said cam on said shaft to' tune the receiver to a given radio station; and said operating lever of said common locking device in said first position controlling said spring biased means to simultaneously unlock said cams on said shaft whereby operation of a selected pushbutton causes the cam associated therewith to be moved relative to said shaft to a position for tuning the receiver to a given radio station, and said operating lever of said common locking device being moved to said second position controlling said spring biased means to simultaneously lock said memory cams on said shaft in position to tune the receiver to thesaid shaft between each of said cams, and spring holding means associated with each spacer to provide sufficient holding force on each of the cams when said operating lever is in said first position so that only those cams which are selectively actuated by its associated pushbutton will rotate about the axis of said shaft during the station set operation.

4. The combination of claim 1 wherein said common locking device further includes a housing having a cavity; an

axial force producing spring in said housing for locking said cams in position on said shaft, and toggle means actuated by said operating lever and being coupled to said spring, with said operating lever in said first position, said toggle means compresses said spring thereby removing its axial force from said 5 cams to unlock the same on said shaft. 

1. In a wave signal receiver having frequency tuning means and pushbuttons to be actuated to set and thereafter recall preselected frequencies of the tuner means to receive given radio stations, the combination including: a housing in which the tuning means is mounted; a shaft mounted in said housing; link means connected between said shaft and said tuning means to cause tuning thereof in response to rotation of said shaft about its axis through a limited arcuate movement; a plurality of memory cams; a common locking device for simultaneously locking and unlocking said cams in position on said shaft, said common locking device including an operating lever movable between first and second positions and spring biased means coupled to said memory cams and being controlled by said operating lever; each of the pushbuttons having a portion thereof extending into said housing and Engaging a respective one of said memory cams to rotate said shaft in response to the position of said cam on said shaft to tune the receiver to a given radio station; and said operating lever of said common locking device in said first position controlling said spring biased means to simultaneously unlock said cams on said shaft whereby operation of a selected pushbutton causes the cam associated therewith to be moved relative to said shaft to a position for tuning the receiver to a given radio station, and said operating lever of said common locking device being moved to said second position controlling said spring biased means to simultaneously lock said memory cams on said shaft in position to tune the receiver to the given radio stations.
 2. The combination of claim 1 wherein said cams are formed having a pair of radially extending portions, and each of said pushbuttons include means extending into said housing to engage one of said radially extending portions and rotate the shaft until said pushbuttons simultaneously engages said pair of radially extending diametrically opposed portions to recall the position of said shaft.
 3. The combination of claim 1 including spacer means on said shaft between each of said cams, and spring holding means associated with each spacer to provide sufficient holding force on each of the cams when said operating lever is in said first position so that only those cams which are selectively actuated by its associated pushbutton will rotate about the axis of said shaft during the station set operation.
 4. The combination of claim 1 wherein said common locking device further includes a housing having a cavity; an axial force producing spring in said housing for locking said cams in position on said shaft, and toggle means actuated by said operating lever and being coupled to said spring, with said operating lever in said first position, said toggle means compresses said spring thereby removing its axial force from said cams to unlock the same on said shaft. 